An Iranian supertanker hauling 130 million dollars (£107m) worth of crude oil that the US suspects is tied to a sanctioned organisation has begun moving away from Gibraltar, marine traffic monitoring data showed late Sunday.

An Iranian supertanker hauling 130 million dollars (£107m) worth of crude oil that the US suspects is tied to a sanctioned organisation has begun moving away from Gibraltar, marine traffic monitoring data showed late Sunday.

The trail left by GPS data on Marinetraffic.com, a vessel tracking service, showed the Iran-flagged Adrian Darya 1, previously known as Grace 1, moving shortly before midnight.

The tanker slowly steered south east toward a narrow stretch of international waters separating Morocco and the southern tip of the Iberian Peninsula.

The vessel had been detained for a month in Gibraltar for allegedly attempting to breach European Union sanctions on Syria.

Gibraltar authorities rejected an eleventh-hour attempt by the United States to reseize the oil tanker, arguing that EU regulations are less strict than US sanctions on Iran.

The vessel’s next destination was not immediately known.

Iran’s ambassador to Britain, Hamid Baeidinejad, had earlier announced on Twitter that the ship was expected to leave Sunday night.

The tanker’s release comes amid a growing confrontation between Iran and the West after US President Donald Trump pulled Washington out of Tehran’s nuclear deal with world powers more than a year ago.

Shortly after the tanker’s detention in early July near Gibraltar, Iran seized the British-flagged oil tanker Stena Impero, which remains held by the Islamic Republic.

Analysts had said the Iranian ship’s release by Gibraltar could see the Stena Impero go free.

Gibraltar’s government said Sunday it was allowing the Iranian tanker’s release because “the EU sanctions regime against Iran – which is applicable in Gibraltar – is much narrower than that applicable in the US”.

In a last-ditch effort to stop the release, the US unsealed a warrant Friday to seize the vessel and its cargo of 2.1 million barrels of light crude oil, citing violations of US sanctions as well as money laundering and terrorism statutes.

US officials told reporters that the oil aboard the ship was worth some 130 million dollars and that it was destined for a designated terror organisation to conduct more terrorism.

The unsealed court documents argued that Iran’s Islamic Revolutionary Guard Corps are the ship’s true owners through a network of front companies.

Authorities in Gibraltar said Sunday that, unlike in the US, Iran’s Revolutionary Guard is not designated a terrorist organisation under EU, UK or Gibraltar law.

The Iranian ship was detained while sailing under a Panamanian flag with the name Grace 1.

As of Sunday, it had been renamed the Adrian Darya 1 and had hoisted an Iranian flag.

Workers were seen painting the new name on the side of the ship Saturday.

Iran has not disclosed the Adrian Darya 1’s intended destination and has denied it was ever sailing for Syria.

The chief minister of Gibraltar, Fabian Picardo, said he had been assured in writing by the Iranian government that the tanker would not unload its cargo in Syria.